This invention relates to multiple mode copying apparatus provided with an optical system capable of varying the multiplication of images formed, and more particularly it is concerned with a multiple mode copying apparatus equipped with a mechanism capable of effecting both magnification and reduction.
In copying apparatus, a light irradiation position for a document to be copied and an exposing position in which a photosensitive member is exposed to an optical image of the document are both fixed, and an optical system for introducing light beams irradiating the document to the photosensitive member includes a lens and mirrors to obtain an overall compact size in a copying apparatus. In such optical system, an optical path is complex to allow the light beams to be reflected several times. The more complicated the optical path, the more complex becomes a magnification varying mechanism.
Heretofore, it has been usual practice for multiple mode copying apparatus to be able to effect copying in the same size as the document to be copied and on a reduced scale. If it is possible to effect copying in the same size as the original, on a reduced scale and an enlarged scale by means of a single device, the utility of the copying apparatus would be enhanced. However, when a single device is relied on for performing copying in the aforesaid triple mode, the following difficulties would be encountered. As subsequently to be described in detail, the lens and mirrors move in the same direction when copying is performed in reduction mode and in the opposite directions when copying is performed in magnification mode. Thus the mechanism would become complex in construction and high in cost if the device were based on the concept of the prior art. Besides, operation could not be performed smoothly.